CVE-2021-23972
CVE-2021-23972 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- CVSS v2: 6.8
- EPSS exploit prediction: 1% (59th percentile)
- Actively exploited: Not listed in CISA KEV
- Affected product: Mozilla Firefox
- Published:
- Last modified:
Description
One phishing tactic on the web is to provide a link with HTTP Auth. For example 'https://[email protected]'. To mitigate this type of attack, Firefox will display a warning dialog; however, this warning dialog would not have been displayed if evil.com used a redirect that was cached by the browser. This vulnerability affects Firefox < 86.
Frequently asked questions
- What is CVE-2021-23972?
- One phishing tactic on the web is to provide a link with HTTP Auth. For example 'https://[email protected]'. To mitigate this type of attack, Firefox will display a warning dialog; however, this warning dialog would not have been displayed if evil.com used a redirect that was cached by the browser. This vulnerability affects Firefox < 86.
- How severe is CVE-2021-23972?
- CVE-2021-23972 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2021-23972 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-23972?
- CVE-2021-23972 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-23972?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2021-23972 published?
- CVE-2021-23972 was published on 2021-02-26 and last updated on 2026-06-17.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1683536
- https://security.gentoo.org/glsa/202104-10
- https://www.mozilla.org/security/advisories/mfsa2021-07/
Affected products (1)
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
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